Question

A study in the Annals of Emergency Medicine found that for emergency room patients in California hospitals the average waiting time— the elapsed time from arrival until seeing a physician— was 56 minutes (source: acep.org). As part of your research at St. Luke’s Hospital in Los Angeles, you track a random sample of 200 patients. The average waiting time for patients in the sample is 60.4 minutes. The sample standard deviation is 28.6 minutes. Is this sample result sufficient to reject a null hypothesis that the average waiting time for patients at St. Luke’s is the same as the overall California average? Use a 5% significance level.